Risk factors for atherosclerotic vascular disease in patients on maintenance hemodialysis--with especial respect to reverse cholesterol transport system and hyperhomocysteinemia

摘要

Hemodialysis (HD) patients have a high mortality rate due to vascular disease (VD). Therefore, we investigated the effect of uremic dyslipidemia on VD in HD patients, with special consideration of the reverse cholesterol transport (RCT) system including high-density-lipoprotein cholesterol (HDL-C), cholesteryl ester transfer protein (CETP) and its genetic (D442G) mutation. In 414 HD patients, a sub-median HDL-C level (< 48 mg/dl) was an independent risk factor for VD. In the lower HDL-C status, the CETP mutation leading to CETP levels was independently associated with VD. In 210 selected patients, the CETP level was an independent protective factor against VD among those with higher HDL-C levels (> 45 mg/dl). We also measured serum homocysteine (Hcy) levels and examined its association with VD considering that hyperhomocysteinemia is a newly identified risk factor for atheroma. HD Patients (n = 545) had about 3 times the Hcy levels of the general population. A common C677T mutation in the gene of methylenetetrahydrofolate reductase (MTHFR) involved in Hcy metabolism was independently and directly related to serum Hcy levels with TT genotype patients having the highest levels. Patients with the TT genotype were younger and had a shorter duration of dialysis than those with the CT or CC genotype after adjustment for age at the initiation of dialysis, although there was no difference in VD prevalence among the genotypes and no association between Hcy levels and VD prevalence. In conclusion, lower HDL-C and CETP status was a risk factor for VD in HD patients, suggesting the importance of RCT. Serum Hcy levels were markedly increased in HD patients and the TT genotype may be associated with higher mortality. However, a large-scale prospective study is required to clarify whether hyperhomocysteinemia or the TT genotype is a VD risk factor among HD patients.